#include<stdio.h>
#include<string.h>
#include<assert.h>
char* my_strcat(char* des, const char* sou)
{
	assert(des && sou);
	char* ret = des;
	while (*des != '\0')
		des++;
	while (*sou != '\0')
		*des++ = *sou++;
	*des = '\0';
		return ret;
}
int main()
{
	char arr1[8] = "spark";
	char arr2[] = "le";
	char arr3[8] = "spark";
	char arr4[] = "le";
	strcat_s(arr1, arr2);
	printf("%s\n", arr1);
	my_strcat(arr3, arr4);
	printf("%s", arr3);
	return 0;
}